1. Field of the Invention
The present invention relates to a glass-cutting apparatus or a glass cutter, and particularly to a glass-cutting apparatus which performs a glass-cutting operation while discharging glass fine particles generated from a cutting glass.
The present application claims priority from Japanese Application No. 2003-163662, the disclosure of which is incorporated herein by reference.
2. Description of the Related Prior Art
Nowadays, as a quantity of industrial wastes increases and begins to exceed a capacity of controlled land fill sites, a reduction of the industrial wastes has become an important problem. Particularly, vehicle window glasses are discarded together with shredder dusts generated by used vehicles, and the quantity of such industrial wastes is enormously large. As for the industrial wastes including the glass, processes of burning the same to take out heat energy have been studied. However, since glass materials can not be easily burnt and are apt to remain as cinders after burning, it causes inconvenience of the need for any further disposal of the cinders. Therefore, some processes of disposing of glasses have been proposed as follows.
Among the glasses, a side door glass is called as a tempered glass, which is broken into grains by hitting it with a hammer, so that the side door glass can be easily collected and discarded. On the other hand, a front glass has a structure in which an intermediate membrane made of resin material is sandwiched between two sheet glasses thereof, and thus it is not easy to break it into fragments. Then, a method of cutting the front glass with a cutting mechanism having a saw blade to discard the cut glass has been proposed (for example, see Japanese Patent Application Laid-Open No. Hei11-310427, in particular FIGS. 3 and 4 thereof).
The cutting mechanism includes the following members: a disc-like diamond cutter mounted on and freely rotated about a central pivot shaft extending sidewardly; a motor for rotationally driving the diamond cutter; a cover for covering an upper portion of the diamond cutter; a stabilizing plate for the cutter mounted on a lower portion of the cover to permit an adjustment of a cut depth in a thickness direction of a front glass through an adjustment of a length by which the diamond cutter protrudes from the under side thereof; and a cooling-water jetting nozzle attached to the cover for downwardly discharging fine particles generated from the front glass cut by the diamond cutter. The cooling-water jetting nozzle is coupled to a high-pressure water supply unit through a tube. For cutting the front glass with the foregoing cutting mechanism, the protrusion of the diamond cutter is adjusted to a certain length by the stabilizing plate, and the diamond cutter is rotationally driven for cutting the front glass, and then water is jetted from the cooling-water jetting nozzle for discharging the fine particles of cut glass downward.
The diamond cutter is protruding from the stabilizing plate for the cutter downward, even under the non-operation. Therefore, there is a danger that an operator touches by mistake on the exposed diamond cutter. Hence, it has been proposed that the cutting mechanism is provided with a safety cover movable between a covering position at which the exposed diamond cutter is covered and a housing position at which the upper portion of diamond cutter is housed in the cover.
However, as the safety cover is so structured that the fine particles generated from the glass in the cutting operation are allowed to enter into a slide space for a central pivot shaft, intrusion of the glass fine particles into the slide space causes a case where the safety cover does not return to the covering position at the time of the non-operation. Thus, there occurs a danger of mistakenly touching the diamond cutter.